Epidemological Studies on the Association between Parasitic Infections and Active Convulsive Epilepsy in Ifakara District, Tanzania

Abstract

Epilepsy is a condition that results into insults that affect the brain, resulting into recurrent seizures unprovoked by any immediate identifiable cause. This condition forms 1% of the global burden of disease. Of the global burden, majority of cases are in developing countries. Parasitic infections are common in developing countries and some of them are associated with the condition and are therefore important in understanding these diseases as risk factors. The main objective of this study was to investigate the prevalence of parasitic infections and the association between these parasitic infections and the development of active convulsive epilepsy (ACE) in Ifakara district of Tanzania. Serum samples were obtained from individuals who had already been screened for epilepsy and confirmed to have ACE with their respective community controls. The serum samples were tested for antibodies to malaria, onchocercosis, toxoplasmosis, toxocariasis and cysticercosis by enzyme linked immunosorbent assay (ELISA) and western blotting. Optical densities on antibody titres to various parasitic diseases in the serum samples were determined by an ELISA reader at 450 nm while immunoblotting strips were used to test for cysticercosis antibodies. Results obtained from the tests for detection of the parasitic infections were analysed statistically by logistic regression to determine statistical odds ratio with a P value of S 0.05 being considered significant. Logistic regression was also used to model the association between parasitic infections’ antibody titres and ACE as well as the relative risk of interaction on multiple parasitic infections. From the findings there were elevated antibody titres to the various parasitic infections with rise in age. The highest prevalence was Plasmodium fizlciparum infection (969.7/1000). ACE was associated with high antibody levels to O. volvulus, 7". canis and T. gondii whereby high antibody levels were significantly associated with increased prevalence of ACE for O. volvulus (OR=1.66; 95% CI: 1.26- 2.l3, p=0.00l), T. canis (OR=2.25; 95% CI: 1.70-2.83, p<0.00l) and T. gandii (OR=l.39; 95% CI: 1.11-1.75, p=0.004). Exposure to P. falciparum on the other hand was not significantly associated with increased n'sk of ACE in Ifakara. In conclusion the study shows that me degree of exposure and multiple parasitic infections are associated With increased prevalence of ACE and may explain conflicting results obtained when only seropositivity is considered since the results obtained demonstrate a strong association between epilepsy and parasitic infections on an additive scale with antibody titres being a better measure of association between epilepsy and parasitic infections. Efforts to control these infections are likely to reduce the burden of epilepsy in SSA.